PRINCETON -- One Princeton University professor works in a lab he likens to a brewery, searching for clues to a mystery that’s rapidly heating up. Another aims to bring durable bridges to the Third World -- in backpacks.

Both are considered geniuses.

Environmental scientist Daniel Sigman and structural engineer Theodore Zoli each received $500,000 awards from the MacArthur Foundation, popularly known as "genius grants." The foundation annually selects about two dozen of the country’s most promising intellectuals, agreeing to support them for five years with no-strings-attached money. An anonymous, 12-member selection committee renders its decision through phone calls placed without warning.

"I was on a conference call and my cell phone started ringing. I picked it up and they asked if I was sitting down," said Zoli, who teaches three hours each week at Princeton and works at an engineering firm in New York. "I certainly didn’t believe it."

Both men were notified last week that their creativity and problem-solving ability would be rewarded. And both will expand their research toward awe-inspiring insights.

Sigman, who teaches and runs a lab with a handful of doctoral students on campus, wants to sharpen the models scientists use to predict changes to climate, soil moisture, rainfall levels and other elements of natural systems. Those models are based on "good physical and biological fundamentals," he said, but lack the complexity that comes with detailed data reaching back far into the past.

In evaluating how global temperatures will change, for instance, "You really need to understand the system at a relatively profound level," Sigman said. "Or you’re going to make a mistake."